During the fight between Marquet and Navarre in the cathedral, Marquet's horse's mane changes constantly from long to short, from thick to thin and at one point it is evident that the horse's mane is a fake.
When the mouse first escapes the dungeon and pops out of the water, it cuts to two soldiers, one of whom is searching for his moneybag. However, the mouse doesn't steal his moneybag until the next scene
At the end of the battle at Imperius' keep, Isabo changes to a hawk as she falls from the top of the keep. Etienne then shoots the last guards after changing from the wolf. But Etienne is fully dressed, and there was no time for him to do so.
Phillipe stands right beside Navarre when he gives him the cloth to wrap the hawk in. However, just afterwards when Navarre tells Phillipe to take the hawk, Phillipe is standing a good couple of metres away from him.
The moon is shown full every night except the night of the struggle on the ice, where it is shown as half full, and then is full again the next night. This is more of a problem because solar eclipses always happen on a new moon (and there is an eclipse in the film).
Also, the Moon is not visible as a black disc (as shown in the film) until the totality phase of a solar eclipse. Before and after totality, only the portion of the Moon that is occulting the Sun is visible. (The Sun's light is strong enough to drown out any view of the Moon when the Moon is near the Sun; moreover, since solar eclipses can only happen at new moon, there is no lit portion of the Moon to be seen anyway.)